A wildfire in Santa Barbara County that’s threatening homes and closing major highways more than doubled in size overnight to 4,000 acres, federal officials said early Friday.

Chewing through vegetation that hasn’t burned since the 1950s and pushed by 40 mph winds, the Sherpa fire crawled toward Highway 101 between El Capitan State Beach and Gaviota, forcing the California Highway Patrol to shut down the coastal route overnight.